There are 13 documented species of otter, 12 of which had declining populations in 2015 and five of which were listed as endangered due to drops in population and destruction of habitat. Exact figures on how many otters still live in the wild across all continents and all species are not readily available as population groups are not uniformly or continuously monitored.
The 13 known species of otter are the African clawless otter, the Asian small-clawed otter, the Congo clawless otter, the sea otter, the North American river otter, the marine otter, the neotropical otter, the South American river otter, the Eurasian otter, the Spotted-Necked otter, the hairy-nosed otter, the smooth-coated otter and the giant otter.
Five of the species known to science are near threatened, five are endangered and two are classified as vulnerable to endangerment. Only one species, the North American river otter, is listed as a species of least concern. The North American river otter also has an upward-trending population.
Otters around the world are decreasing in number due to various factors including pollution, human encroachment on and destruction of their habitats and other problems afflicting their populations. In 2015, their predicament was an extreme one and many species were at risk for extinction.